1. Field of the Invention
The invention relates to a solid state actuator arrangement comprising a bending actuator having an extension element fastened to a free end of the actuator.
2. Prior Art
A solid state actuator arrangement comprising an actuator, designed as a solid state bending actuator, is known in general. The actuator has, opposite one another, a first and a second end portion. Moreover, the solid state actuator arrangement comprises a fastening device for a misplacement-proof fastening of the first end portion of the actuator to a frame or a housing. Furthermore, the solid state actuator arrangement has a control device or terminals for applying a driver signal to the actuator, so that, by the actuator being bent due to the applied driver signal, the second end portion can be adjusted in relation to the first end portion between at least two positions, in particular continuously adjusted. By the second end portion a switching action can thereby be initiated, or a body can be adjusted or moved in relation to the fastening device and consequently in relation to a frame or housing.
In particular, by a solid state actuator arrangement, a piezoelectric stepping motor, based on piezoelectric bending actuators, can be developed for the drive of indicator instruments in the form of a pointer drive. Indicator instruments of this type may be used as revolution counters, tachometers or temperature indicators as an integral part of a combination instrument for vehicles, in particular passenger cars, motor trucks or motor boats. Accordingly, solid state actuator arrangements of this type are mass products subject to stringent cost constraints.
In the case of stepping motors based on piezoelectric bending actuators as solid state actuators, the cost situation is dominated by the price of the piezoelectric bending actuators which are employed. A rough estimation of costs leads to two proportional relationships. The costs for the bending actuators are directly proportional to their volume. Moreover, the mechanical power of the actuator excited the driver signal is directly proportional to its volume.
Performance data, specified in the product definitions for a stepping motor formed from such a solid state actuator arrangement stipulate the necessary minimum volume of the piezoelectric actuators to be used, this ultimately determining the costs of the stepping motor.
It can be seen from the relationships that high costs for actuators of this type are a disadvantage. On account of the direct relationship between the costs and volume of such an actuator, there is therefore the technical problem of increasing the mechanical power output per actuator volume when such an actuator is activated, so that the costs of manufacturing a solid state actuator arrangement can be lowered to the same extent, since less actuator material has to be used in order to fulfill a given specification.